Remarkably stable and efficient Ni and Ni-Co catalysts for CO2 methanation

CO2 methanation is one of the most promising ways to store energy based on the power-to-gas concept. In this study, efficient nickel (Ni) and nickel-cobalt (Ni-Co), supported on alumina catalysts with different amounts of Ni and Co were prepared, characterized and used for CO2 methanation under the atmospheric pressure. The catalysts were prepared in the form of extrudates for catalytic tests. The effect of Ni content and the influence of Co on Ni catalysts were studied in a packed bed methanation reactor at laboratory scale. An optimal Ni-Co content was identified based on CO2 and H-2 conversion and CH4 selectivity and yield. The addition of Co improved the reducibility of Ni species and Ni particles' dispersion over the support. Therefore, the presence of Co enhanced the catalyst activity and selectivity towards CH4. Moreover, it was observed that low reaction temperatures (lower than 350 degrees C) can be used when lowering the Ni content (i.e. 10% wt.). This major fact is favourable to the reduction of the overall process energy consumption and to the decrease of the catalysts' deactivation at high temperature (> 400 degrees C), such as the active phase sintering. Finally, the Ni and Ni-Co catalysts prepared in this work for CO2 methanation presented a remarkably high stability over 200 h of continuous reaction.